1. Field of the Invention
This invention relates to a means which will convert a positive static electrically charged glass surface to a negative static electrically charged surface so that it will repel human fibers, dust and silica based dirt.
2. Description of the Related Art
House dust contains human negative static electrically charged fibers and other particles. This dust will attach to positive static electrically charged glass windows, mirrors and other glass objects. Typical dust cleaning solutions for glass use water and a surfactant to remove surface dust; however, because the surfaces remain positive static electrically charged, negative static electrically charged dust will recoat the positive static electrically charged substrates.
U.S. Pat. No. 4,511,489 to Requejo, et al issued on Apr. 16, 1985, refers to a cleaning and polishing composition for acrylic plastic substrates, including Plexiglas, Lucite, Lexan and the like. An aqueous dispersion of a fluid silicone oil, such as polydimethyl siloxane, a nonionic or anionic surfactant, such as sodium lauryl sulfate, and a fluorinated organic surface-active compound are mixed with water and is applied to the plastic surface, after which the plastic surface is dried with a paper towel or other device. The amount of silicone applied varies from about 0.5% to 10% by weight of the of the cleaning composition, preferably 1 to 5% by weight, especially preferably about 2% by weight, based on the total composition, on an active basis. The viscosity of the silicone oil varies from 40 to 100,000 centistokes, preferably from 40 to 1000 centistokes and most preferably from 200 to 500 centistokes.
The patent claims that these compositions provide dust repelling, cleaning and polishing, especially suitable for Plexiglass and other acrylic plastic materials. The patent also asserts that this treatment provides a thin lubricating coating on the plastic substrate which causes the treated surface to become smooth, slippery and electrostatically inert, thereby preventing the collection of dust, oil, grime and other soils on the surface.
The fact that the inventor of U.S. Pat. No. 4,511,489 refers to the static electrical nature of the composition of the invention as being inert and antistatic indicates that the composition does not retain a net negative static electrical charge on the surface after application. The characteristic of being “antistatic” means that the material discharges or neutralizes the static charge on the surface. Discharging is commonly accomplished with an electrolyte, including water with dissolved ions, which can conduct electrical charge and therefore can discharge a statically charged surface. Although discharging a positively charged surface will help reduce the attraction between the surface and negatively charged, airborne particles, it is preferable to provide a negatively charged surface, rather than a neutral surface, in order to actively repel those particles. The surface can also be discharged by providing sufficient negative charge to neutralize the positive surface charge. However, for a water soluble material, while an amount of negative charge equal to the positive surface charge can be held on the positive charged surface by the electrical field attraction, if the material is water soluble, any excess beyond the amount to cause neutralization will be discharged and/or removed by water in the product or rain and/or atmospheric moisture.
Referring to the Triboelectricity series, acrylic plastic surfaces such as Lucite do not retain a static electrical charge since they are in the middle of the chart. They retain neither positive static electrical nor negative electrical charges. The antistatic film composition used on the Lucite was electrostatically inert, but must have had some small negative static electrical charge to repel dust for a period of 3 days to 2 weeks. However, it did fail to repel dust after this 2 week period.
In the case of glass windows and mirrors, the positive static electrical charge of the glass is large since glass stands near the top of the positive static electrical portion of the Triboelectric Series chart. It therefore takes a strong negative static electrical charge of the silicone to overcome the strong positive static electrical charge of the glass mirror or window. The cleaning and polishing silicone compositions used in U.S. Pat. No. 4,511,489 were antistatic and inert; thereby they would be too weak to overcome the strong positive static electrical charge of the glass.
Enclosed areas, such as homes and the inside of automobiles, are subjected to dust and human skin fibers, which coat susceptible surfaces. These surfaces, such as glass mirrors, glass windows and the inside glass surfaces of an automobile are static electrically positively charged and will attract negative static electrically charged human fibers and dust. Washing the glass surface with water and detergent mixtures will remove the dust and human fibers, but the cleaned surface will reattract the dust and human fibers because there is a static electrical attraction between the positive static electrically charged surface and the negative static electrically charged human fibers and dust.
The object of the present invention is to provide a strong negative static electrically charged liquid composition which will not only neutralize the strong positive static electrical charge on the glass surface, but will provide a negative electrical surface charge that is durable so it will remain effective for an effective, practically useful period of time after application, even up to a year.
Dust may contain fabric fibers, human skin particles, animal dander, and microscopic creatures called mites. Bacteria, mold spores, food particles and other debris. The static electrical charge on these particles is negative. These particles and fibers will adhere to positive static electrically charged surfaces. Coating of these surfaces with a strong, thin, negative static electrically charged coating will inhibit the adhesion of these particles to the surface. The coating should be thin because thicker coatings may cause streaking.
Outside dirt is primarily based on silica, which has a negative static electrical charge. Coating a surface such as the outside of a window or the outside of an automobile windshield with a negative static electrically charged coating will also inhibit silica based dirt attachment to the glass.